HIGH TEMPERATURE CERAMIC STRUCTURES

INVESTIGATIONS WERE CONCERNED WITH (1) radome fabrication and material evaluations, and (2) arc-plasma flame glazing of slip cast fused silica. The larger effort was expended in the latter area. A procedure was developed for pressure casting radomes from fused silica slip, which provided a casting time of 80 min, which was an approximate reduction of 9 hr in casting time using conventional slip-casting procedures, to form a 3/8-in. thick x 15-in. diam x 32-in. high radome. The effect of pressure casting on the slip properties of the drained slip was determined by particle size analysis, percentage solids concentration, and slip density. The results indicated that the properties of the drained slip were not affected by pressure casting; and therefore, the drained slip could be reused repeatedly. A furnace to facilitate firing large radome shapes was designed and constructed. It is capable of firing slip-cast fused silica radomes up to 15-in. in diam x 32-in. in height to a temperature to 2600 F. Radomes can be loaded or unloaded in this furnace in approximately 2-4 minutes with a drop in furnace temperature during this period of only 150 F. (Author)